CLIMBING FIBER RESPONSES IN CEREBELLAR VERMAL PURKINJE-CELLS DURING PERTURBED LOCOMOTION IN DECEREBRATE CATS

We recorded spike potentials from Purkinje cells in the lateral vermis of lobule V in cat cerebellum, and found significant enhancement in c limbing fiber discharges during perturbed locomotion. Five adult cats were decerebrated at a precollicular level, and 4-5 days thereafter, t hey were mounted on a treadmill. During stable locomotion at 36 cm/s b elt velocity, climbing fiber responses were slightly modulated with a weak increment at the swing phase of the ipsilateral forelimb. When th e left contralateral forelimb alone was suddenly imposed with a faster belt velocity of 61 cm/s, the occurrence of the climbing fiber discha rges was significantly enhanced during the late swing phase of the ips ilateral forelimb. This observation is in accordance with the general notion that climbing fiber responses represent error signals in contro l of movements.